#!/usr/bin/env python3
# -*- coding: utf-8 -*-

class Student(object):
    __slots__ = ('name','age')

class GraduateStudent(object):
    pass
s = Student()
s.name = 'wkx'
s.age = 23
try:
    s.height = 175
except AttributeError as e:
    print('AttributeError:',e)
g = GraduateStudent()
g.height = 175
print('g.height=',g.height)
